To estimate a maximum purchase price for the coin in question, we can analyze the provided data and consider several factors:

1. Current Condition: The coin has a condition of 85 (ebc-), which indicates that it is in quite good shape. This is important because coins in better condition tend to reach higher prices.

2. Previous Auction Prices: Looking at previous auction prices for coins with similar conditions:
- In 2020, a coin with a condition of 85 was auctioned for 2500 euros.
- In 2019, a coin with a condition of 90 was auctioned for 2800 euros.
- In 2014, a coin with a condition of 80 was auctioned for 600 euros.

3. Starting Price and Average Auction Price: The current starting price is 2500 euros, and the average auction price in the past has been 1960 euros. This suggests that the starting price is aligned with previous auction prices.

4. Auction Trends: The coin has been auctioned 10 times and has sold on all occasions, indicating consistent demand.

5. Maximum Price Estimate: Given that the condition is good and considering previous auction prices, a maximum purchase price could be in the range of 2500 to 2800 euros, as this reflects both the starting price and the auction prices of coins with similar conditions.

Conclusion: An estimated maximum purchase price for this coin could be approximately 2800 euros. This is based on the condition, previous auction prices, and demand trends.